Color forming composition containing a plurality of antenna dyes

ABSTRACT

A radiation image-able coating includes a first phase including a radiation curable polymer matrix and an activator disposed in the radiation curable polymer matrix, a second phase insolubly distributed in the first phase, the second phase including a color-former, and a hybrid antenna dye package distributed in at least one of the first and second phase, wherein the hybrid antenna dye package includes at least a first antenna dye having a high extinction coefficient and a second antenna dye having a low extinction coefficient.

BACKGROUND

Compositions that produce a color change upon exposure to energy in theform of light or heat are of great interest in generating images on avariety of substrates. For example, data storage media provide aconvenient way to store large amounts of data in stable and mobileformats. For example, optical discs, such as compact discs (CDs),digital video disks (DVDs), or other discs allow a user to storerelatively large amounts of data on a single relatively small medium.Traditionally, commercial labels were frequently printed onto opticaldiscs by way of screen printing or other similar methods to aid inidentification of the contents of the disk.

Current efforts have been directed to providing consumers with theability to store data on optical disks using drives configured to burndata on recordable compact discs (CD-R), rewritable compact discs(CD-RW), recordable digital video discs (DVD-R), rewritable digitalvideo discs (DVD-RW), and combination drives containing a plurality ofdifferent writeable drives, to name a few. The optical disks used asstorage mediums frequently have two sides: a data side configured toreceive and store data and a label side. The label side is traditionallya background on which the user hand writes information to identify thedisc.

Recent developments have provided for the imaging of a dye-containingcoating with the lasers of commercially available optical disk drives.However, dyes used in traditional image-able coatings have either hadhigh radiation absorption efficiency and low fade resistance, or lowradiation absorption efficiency with high fade resistance and stability.

SUMMARY

A radiation image-able coating includes a first phase including aradiation curable polymer matrix and an activator disposed in theradiation curable polymer matrix as well as a second phase insolublydistributed in the first phase, the second phase including acolor-former, and a hybrid antenna dye package distributed in at leastone of the first and second phase, wherein the hybrid antenna dyepackage includes at least a first antenna dye having a high extinctioncoefficient and a second antenna dye having a low extinctioncoefficient.

Additionally, according to one exemplary embodiment, a method forforming a radiation image-able coating includes preparing aradiation-curable polymer matrix including an acidic activator species,forming a low-melting eutectic of a leuco-dye phase, distributing thelow-melting eutectic of a leuco-dye phase in the polymer matrix, andsensitizing the radiation imageable coating with a hybrid antenna dyepackage, the hybrid antenna dye package including at least a firstantenna dye having a high extinction coefficient and a second antennadye having a high extinction coefficient.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments of the presentsystem and method and are a part of the specification. The illustratedembodiments are merely examples of the present system and method and donot limit the scope of the disclosure.

FIG. 1 illustrates a schematic view of a media processing systemaccording to one exemplary embodiment.

FIG. 2 is a flowchart illustrating a method of forming an imageablecomposition according to one exemplary embodiment.

FIG. 3 is a flowchart illustrating a method for forming a radiationimage-able composition, according to one exemplary embodiment.

FIG. 4 is a flow chart illustrating a method for forming a radiationimage-able composition, according to one exemplary embodiment.

FIG. 5 is a flow chart illustrating a method for forming an image on aradiation image-able coating, according to one exemplary embodiment.

Throughout the drawings, identical reference numbers designate similar,but not necessarily identical, elements.

DETAILED DESCRIPTION

The present exemplary systems and methods provide for the preparation ofa two-phase radiation image-able thermochromic coating having improvedmarking sensitivity and shelf-life reliability. In particular, aradiation-curable radiation imageable coating is described herein thatcan be imaged with a radiation generating device while exhibiting highmarking sensitivity combined with relatively good shelf-lifereliability. According to one exemplary embodiment, the presenttwo-phase radiation image-able thermochromic coating has two or moreantenna dyes dispersed and/or dissolved in various phases of thecoating, a first of the two or more antenna dyes exhibits a highradiation absorbance due to a high extinction coefficient, and a secondof the two or more antenna dyes exhibits a robust fade resistance andgenerally good stability, which very often comes at expense ofsignificantly lower extinction coefficient. Further details of thepresent coating, as well as exemplary methods for forming the coatingson a desired substrate will be described in further detail below.

As used in the present specification, and in the appended claims, theterm “radiation image-able discs” is meant to be understood broadly asincluding, but in no way limited to, audio, video, multi-media, and/orsoftware disks that are machine readable in a CD and/or DVD drive, orthe like. Non-limiting examples of radiation image-able disc formatsinclude, writeable, recordable, and rewriteable disks such as DVD,DVD-R, DVD-RW, DVD+R, DVD+RW, DVD-RAM, CD, CD-ROM, CD-R, CD-RW, and thelike.

For purposes of the present exemplary systems and methods, the term“color” or “colored” refers to absorbance and reflectance propertiesthat are preferably visible, including properties that result in black,white, or traditional color appearance. In other words, the terms“color” or “colored” includes black, white, and traditional colors, aswell as other visual properties, e.g., pearlescence, reflectivity,translucence, transparency, etc.

In the following description, for purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present systems and methods for forming a two-phaseradiation image-able coating with improved marking sensitivity andshelf-life reliability. It will be apparent, however, to one skilled inthe art that the present systems and methods may be practiced withoutthese specific details. Reference in the specification to “oneembodiment” or “an embodiment” means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. The appearance of the phrase “inone embodiment” in various places in the specification are notnecessarily all referring to the same embodiment.

EXEMPLARY STRUCTURE

FIG. 1 illustrates a schematic view of a media processing system (100),according to one exemplary embodiment. As will be described in moredetail below, the illustrated media processing system (100) allows auser, among other things, to expose a radiation image-able surface withcoatings of the present exemplary compositions, register an image on thecoatings, and use the imaged object for a variety of purposes. Forexample, according to one exemplary embodiment, a radiation image-abledata storage medium (radiation image-able disc) may be inserted into themedia processing system (100) to have data stored and/or a graphic imageformed thereon. As used herein, for ease of explanation only, thepresent dual band radiation image-able thermochromic coating will bedescribed in the context of coating an optical disk such as a compactdisk (CD) or a digital video disk (DVD). However, it will be understoodthat the present dual band radiation image-able thermochromic coatingmay be applied to any number of desired substrates including, but in noway limited to, polymers, papers, metal, glass, ceramics, and the like.

As illustrated in FIG. 1, the media processing system (100) includes ahousing (105) that houses a radiation generating device (110), which maybe controllably coupled to a processor (125). The operation of theradiation generating device (110) may be controlled by the processor(125) and firmware (123) configured to selectively direct the operationof the radiation generating device. The exemplary media processingsystem (100) also includes hardware (not shown), such as spindles,motors, and the like, for placing a radiation image-able disc (130) inoptical communication with the radiation generating device (110). Theoperation of the hardware (not shown) may also be controlled by firmware(123) accessible by the processor (125). The above-mentioned componentswill be described in further detail below.

As illustrated in FIG. 1, the media processing system (100) includes aprocessor (125) having firmware (123) associated therewith. As shown,the processor (125) and firmware (123) are shown communicatively coupledto the radiation generating device (110), according to one exemplaryembodiment. Exemplary processors (125) that may be associated with thepresent media processing system (100) may include, without limitation, apersonal computer (PC), a personal digital assistant (PDA), an MP3player, or other such device. According to one exemplary embodiment, anysuitable processor may be used, including, but in no way limited to aprocessor configured to reside directly on the media processing system.Additionally, as graphically shown in FIG. 1, the processor (125) mayhave firmware (123) such as software or other drivers associatedtherewith, configured to control the operation of the radiationgenerating device (110) to selectively apply radiation to the datastorage medium (130). According to one exemplary embodiment, thefirmware (123) configured to control the operation of the radiationgenerating device (110) may be stored on a data storage device (notshown) communicatively coupled to the processor (125) including, but inno way limited to, read only memory (ROM), random access memory (RAM),and the like.

As introduced, the processor (125) is configured to controllablyinteract with the radiation generating device (110). While FIG. 1illustrates a single radiation generating device (110), any number ofradiation generating devices may be incorporated in the media processingsystem (100). According to one exemplary embodiment, the radiationgenerating device (110) may include, but is in no way limited to aplurality of lasers configured for forming data on a CD and/or DVD, suchas in a combo CD/DVD recording drive. More specifically, a combo CD/DVDrecording drive configured to record on more than one type of media maybe incorporated by the media processing system (100). For example, aDVD-R/RW (+/−) combo drive is also capable of recording CD-R/RW forexample. In order to facilitate recording on more than one type ofmedia, these combo CD/DVD recording drives include more than one laser.For example combo CD/DVD recording drives often contain 2 recordinglasers: a first laser operating at approximately 780 nm for CDrecordings and a second laser operating at approximately 650 nm for DVDrecordings. Accordingly, the present media processing system (100) mayinclude any number of lasers having wavelengths that may vary frombetween approximately 200 nm to approximately 1200 nm.

As mentioned previously, the present media processing system (100)includes a data storage medium in the form of a radiation imageable disk(130) disposed adjacent to the radiation generating device (110).According to one exemplary embodiment, the exemplary radiationimage-able disc (130) includes first (140) and second (150) opposingsides. The first side (140) has a data surface formed thereon configuredto store data while the second side (150) includes a radiationimage-able surface having a dual band color forming composition.

With respect to the first side (140) of the radiation image-able disk(130), the radiation generating device (110) may be configured to readexisting data stored on the radiation image-able disk (130) and/or tostore new data on the radiation image-able disc (130), as is well knownin the art. As used herein, the term “data” is meant to be understoodbroadly as including the non-graphic information digitally or otherwiseembedded on a radiation imageable disc. According to the presentexemplary embodiment, data can include, but is in no way limited to,audio information, video information, photographic information, softwareinformation, and the like. Alternatively, the term “data” may also beused herein to describe information such as instructions a computer orother processor may access to form a graphic display on a radiationimage-able surface.

In contrast to the first side of the radiation image-able disk (130),the second side of the radiation image-able disk (140) includes atwo-phase radiation image-able coating exhibiting improved markingsensitivity and shelf-life reliability compared to traditionalimage-able coatings. According to one exemplary embodiment, discussed infurther detail below, the second side of the radiation image-able disk(140) includes two separate phases: a first phase including aradiation-curable polymer matrix with an acidic activator speciesdissolved therein, and a second phase including a low-melting eutecticof a leuco-dye insoluble in the polymer matrix but uniformly distributedtherein as a fine dispersion. Additionally, two or more antenna dyes aredispersed and/or dissolved in the two phases of the coating. Furtherdetails of the radiation-curable radiation image-able coating exhibitingboth marking sensitivity and good shelf-life reliability will beprovided below.

EXEMPLARY COATING FORMULATION

As mentioned above, the second side of the radiation imageable disk(140) includes a number of components forming two separate phasesconfigured to be imaged by one or more lasers emitting radiation at aknown wavelength. According to one exemplary embodiment, the twoseparate phases forming the present coating formulation include, but arein no way limited to, a radiation-curable polymer matrix with acidicactivator species dissolved therein and a low-melting eutectic of aleuco-dye insoluble in the matrix but uniformly distributed therein as afine dispersion. Additionally, the coating formulation is sensitized bythe inclusion of a hybrid antenna dye package uniformlydistributed/dissolved in at least one and preferably both phase(s) ofthe coating. If the present hybrid antenna dye package is present inonly one phase, image formation may be enhanced by distributing thehybrid antenna dye package in the radiation-curable polymer matrixphase. According to one exemplary embodiment, the present hybrid antennadye package includes at least two dyes, at least one dye having a highradiation absorbance due to a high extinction coefficient and at least asecond dye having a robust fade resistance and generally good stabilityquite often associated with lower extinction coefficient. Each of thepresent phases will be described in detail below.

As mentioned, the first phase of the dual band radiation imageablethermochromic coating includes, but is in no way limited to, aradiation-curable polymer matrix with acidic activator species dissolvedtherein. According to one exemplary embodiment, the radiation curablepre-polymer, in the form of monomers or oligomers, may be a lacquerconfigured to form a continuous phase, referred to herein as a matrixphase, when exposed to light having a specific wavelength. Morespecifically, according to one exemplary embodiment, the radiationcurable polymer may include, by way of example, UV-curable matrices suchas acrylate derivatives, oligomers, and monomers, with a photo package.A photo package may include a light absorbing species, such asphotoinitiators, which initiate reactions for curing of the lacquer,such as, by way of example, benzophenone derivatives. Other examples ofphotoinitiators for free radical polymerization monomers and oligomersinclude, but are not limited to, thioxanethone derivatives,anthraquinone derivatives, acetophenones, benzoine ethers, and the like.

According to one exemplary embodiment, the radiation-curable polymermatrix phase may be chosen such that curing is initiated by a form ofradiation that does not cause a color change of the color-former presentin the coating, according to the present exemplary system and method.For example, the radiation-curable polymer matrix may be chosen suchthat the above-mentioned photo package initiates reactions for curing ofthe lacquer when exposed to a light having a different wavelength thanthat of the leuco dyes. Matrices based on cationic polymerization resinsmay require photoinitiators based on aromatic diazonium salts, aromatichalonium salts, aromatic sulfonium salts and metallocene compounds. Asuitable lacquer or matrix may also include Nor-Cote CLCDG-1250A (amixture of UV curable acrylate monomers and oligomers) which contains aphotoinitiator and organic solvent acrylates. Other suitable componentsfor lacquers or matrices may include, but are not limited to, acrylatedpolyester oligomers, such as CN293 and CN294 as well as CN-292 (lowviscosity polyester acrylate oligomer), trimethylolpropane triacrylatecommercially known as SR-351, isodecyl acrylate commercially known asSR-395, and 2(2-ethoxyethoxy)ethyl acrylate commercially known asSR-256, all of which are commercially available from Sartomer Co.

Additionally, a number of acidic developers may be dispersed/dissolvedin the present radiation curable polymer matrix. According to oneexemplary embodiment, the acidic developers present in the radiationcurable polymer matrix may include a phenolic species capable ofdeveloping color when reacting with a leuco dye and soluble or partiallysoluble in the coating matrix phase. Suitable developers for use withthe present exemplary system and method include, but are in no waylimited to, acidic phenolic compounds such as, for example, Bis-PhenolA, p-Hydroxy Benzyl Benzoate, Bisphenol S (4,4-DihydroxydiphenylSulfone), 2,4-Dihydroxydiphenyl Sulfone, Bis(4-hydroxy-3-allylphenyl)sulfone (Trade name—TG-SA), 4-Hydroxyphenyl-4′-isopropoxyphenyl sulfone(Trade name—D8). The acidic developer may be either completely or atleast partially dissolved in the UV-curable matrix.

The second phase of the present two-phase radiation imageablethermochromic coating with improved marking sensitivity and shelf-lifereliability is a color-former phase including, according to oneexemplary embodiment, a leuco-dye and/or leuco-dye alloy, furtherreferred to herein as a leuco-phase. According to one exemplaryembodiment, the leuco-phase is present in the form of small particlesdispersed uniformly in the exemplary coating formulation. According toone exemplary embodiment, the leuco-phase includes leuco-dye or alloy ofleuco-dye with a mixing aid configured to form a lower melting eutecticwith the leuco-dye. Alternatively, according to one embodiment, thesecond phase of the present radiation curable polymer matrix may includeother color forming dyes such as photochromic dyes.

According to one exemplary embodiment, the present two-phase radiationimage-able thermochromic coating may have any number of leuco dyesincluding, but in no way limited to, fluorans, phthalides,amino-triarylmethanes, aminoxanthenes, aminothioxanthenes,amino-9,10-dihydro-acridines, aminophenoxazines, aminophenothiazines,aminodihydro-phenazines, aminodiphenylmethanes, aminohydrocinnamic acids(cyanoethanes, leuco methines) and corresponding esters,2(phydroxyphenyl)-4,5-diphenylimidazoles, indanones, leuco indamines,hydrozines, leuco indigoid dyes, amino-2,3-dihydroanthraquinones,tetrahalop, p′-biphenols, 2(p-hydroxyphenyl)-4,5-diphenylimidazoles,phenethylanilines, and mixtures thereof. According to one particularaspect of the present exemplary system and method, the leuco dye can bea fluoran, phthalide, aminotriarylmethane, or mixture thereof. Severalnonlimiting examples of suitable fluoran based leuco dyes include, butare in no way limited to, 3-diethylamino-6-methyl-7-anilinofluorane,3-(N-ethyl-p-toluidino)-6-methyl-7-anilinofluorane,3-(N-ethyl-N-isoamylamino)-6-methyl-7-anilinofluorane,3-diethylamino-6-methyl-7-(o,p-dimethylanilino)fluorane,3-pyrrolidino-6-methyl-7-anilinofluorane,3-piperidino-6-methyl-7-anilinofluorane, 3-(N-cyclohexyl-Nmethylamino)-6-methyl-7-anilinofluorane,3-diethylamino-7-(mtrifluoromethylanilino) fluorane,3-dibutylamino-6-methyl-7-anilinofluorane,3-diethylamino-6-chloro-7-anilinofluorane,3-dibutylamino-7-(o-chloroanilino) fluorane,3-diethylamino-7-(o-chloroanilino)fluorane,3-di-n-pentylamino-6-methyl-7-anilinofluoran,3-di-n-butylamino-6-methyl-7-anilinofluoran,3-(n-ethyln-isopentylamino)-6-methyl-7-anilinofluoran,3-pyrrolidino-6-methyl-7-anilinofluoran,1(3H)-isobenzofuranone,4,5,6,7-tetrachloro-3,3-bis[2-[4-(dimethylamino)phenyl]-2-(4-methoxyphenyl)ethenyl],and mixtures thereof.

Aminotriarylmethane leuco dyes can also be used in the present inventionsuch as tris(N,N-dimethylaminophenyl) methane (LCV);tris(N,N-diethylaminophenyl)methane (LECV);tris(N,N-di-n-propylaminophenyl) methane (LPCV);tris(N,N-dinbutylaminophenyl) methane (LBCV);bis(4-diethylaminophenyl)-(4-diethylamino-2-methyl-phenyl) methane(LV-1); bis(4-diethylamino-2-methylphenyl)-(4-diethylamino-phenyl)methane (LV-2); tris(4-diethylamino-2-methylphenyl) methane (LV-3);bis(4-diethylamino-2-methylphenyl)(3,4-dimethoxyphenyl) methane (LB-8);aminotriarylmethane leuco dyes having different alkyl substituentsbonded to the amino moieties wherein each alkyl group is independentlyselected from C1-C4 alkyl; and aminotriaryl methane leuco dyes with anyof the preceding named structures that are further substituted with oneor more alkyl groups on the aryl rings wherein the latter alkyl groupsare independently selected from C1-C3 alkyl.

Additional leuco dyes can also be used in connection with the presentexemplary systems and methods and are known to those skilled in the art.A more detailed discussion of appropriate leuco dyes may be found inU.S. Pat. Nos. 3,658,543 and 6,251,571, each of which are herebyincorporated by reference in their entireties. Additionally examples maybe found in Chemistry and Applications of Leuco Dyes, Muthyala, Ramaiha,ed.; Plenum Press, New York, London; ISBN: 0-306-45459-9, incorporatedherein by reference.

Further, according to one exemplary embodiment, a number of melting aidsmay be included with the above-mentioned leuco dyes. As used herein, themelting aids may include, but are in no way limited to, crystallineorganic solids with melting temperatures in the range of approximately50° C. to approximately 150° C., and preferably having meltingtemperature in the range of about 70° C. to about 120° C. In addition toaiding in the dissolution of the leuco-dye and the antenna dye, theabove-mentioned melting aid may also assist in reducing the meltingtemperature of the leuco-dye and stabilize the leuco-dye alloy in theamorphous state, or slow down the re-crystallization of the leuco-dyealloy into individual components. Suitable melting aids include, but arein no way limited to, aromatic hydrocarbons (or their derivatives) thatprovide good solvent characteristics for leuco-dye and antenna dyes usedin the present exemplary systems and methods. By way of example,suitable melting aids for use in the current exemplary systems andmethods include, but are not limited to, m-terphenyl, pbenzyl biphenyl,alpha-naphtol benzylether, 1,2[bis(3,4]dimethylphenyl)ethane. In someembodiments, the percent of leuco dyes or other color-former and meltingaid can be adjusted to minimize the melting temperature of thecolor-former phase without interfering with the development propertiesof the leuco dye. When used, the melting aid can comprise fromapproximately 2 wt % to approximately 25 wt % of the color-former phase.

According to one embodiment of the present exemplary system and method,the above-mentioned leuco-phase is uniformly dispersed or distributed inthe matrix phase as a separate phase. In other words, at ambienttemperature, the leuco phase is practically insoluble in matrix phase.Consequently, the leuco-dye and the acidic developer component of thematrix phase are contained in the separate phases and can not react withcolor formation at ambient temperature. However, upon heating with laserradiation, both phases melt and mix. Once mixed together, color isdeveloped due to a reaction between the fluoran leuco dye and the acidicdeveloper. According to one exemplary embodiment, when the leuco dye andthe acidic developer melt and react, proton transfer from the developeropens a lactone ring of the leuco-dye, resulting in an extension ofconjugate double bond system and color formation.

While the above-mentioned color formation is desired, the formation ofthe color is further controlled and facilitated by sensitizing thevarious phases of the resulting coating to a known radiation emissionwavelength via the use of a plurality of antenna dyes, thereby providingmaximum heating efficiency. According to one exemplary embodiment, theantenna dyes comprise a number of radiation absorbers configured tooptimize development of the color forming composition upon exposure toradiation at a predetermined exposure time, energy level, wavelength,etc. More specifically, the radiation absorbing antenna dyes may act asan energy antenna providing energy to surrounding areas of the resultingcoating upon interaction with an energy source of a known wavelength.Once energy is received by the radiation absorbing antenna dyes, theradiation is converted to heat to melt portions of the coating andselectively induce image formation. However, radiation absorbing dyeshave varying absorption ranges and varying absorbency maximums where theantenna dye will provide energy most efficiently from a radiationsource. Generally speaking, a radiation antenna that has a maximum lightabsorption at or in the vicinity of a desired development wavelength maybe suitable for use in the present system and method.

As a predetermined amount and frequency of radiation is generated by theradiation generating device (110) of the media processing system (100),matching the radiation absorbing energy antenna to the radiationwavelengths and intensities of the first and second radiation generatingdevices can optimize the image formation system. Optimizing the systemincludes a process of selecting components of the color formingcomposition that can result in a rapidly developable composition under afixed period of exposure to radiation at a specified power.

According to one exemplary embodiment, the present two-phase radiationimage-able coating having improved marking sensitivity and shelf-lifereliability includes a hybrid antenna package uniformlydistributed/dissolved in at least one and preferably both phase(s) ofthe coating including two or more antenna dyes that may be divided intotwo groups. According to the present exemplary embodiment, the two ormore antenna dyes included in the present hybrid antenna package may beselected from a number of radiation absorbers such as, but not limitedto, aluminum quinoline complexes, porphyrins, porphins, indocyaninedyes, phenoxazine derivatives, phthalocyanine dyes, polymethyl indoliumdyes, polymethine dyes, guaiazulenyl dyes, croconium dyes, polymethineindolium dyes, metal complex IR dyes, cyanine dyes, squarylium dyes,chalcogeno-pyryloarylidene dyes, indolizine dyes, pyrylium dyes, quinoiddyes, quinone dyes, azo dyes, and mixtures or derivatives thereof. Othersuitable antennas can also be used in the present exemplary system andmethod and are known to those skilled in the art and can be found insuch references as “Infrared Absorbing Dyes”, Matsuoka, Masaru, ed.,Plenum Press, New York, 1990 (ISBN 0-306-43478-4) and “Near-InfraredDyes for High Technology Applications”, Daehne, Resch-Genger, Wolfbeis,Kluwer Academic Publishers (ISBN 0-7923-5101-0), both incorporatedherein by reference.

According to the present exemplary embodiment, the two or more antennadyes included in the present hybrid antenna package may be separatedinto a high sensitivity/lower stability dye group or a lowersensitivity/high stability dye group. According to one exemplaryembodiment, the antenna dyes may be classified as either highsensitivity or low sensitivity according to the extinction coefficientof the antenna dye. As used herein, the term high sensitivity/lowerstability dye shall be understood to mean an antenna dye having anextinction coefficient greater than approximately 100000 L Mol⁻¹ Cm⁻¹.Similarly, according to one exemplary embodiment, the term lowsensitivity/higher stability dye shall be understood to mean an antennadye having an extinction coefficient less than approximately 1000000 LMol⁻¹ Cm⁻¹. In addition to providing a hybrid antenna package havingboth antenna dyes of high sensitivity/lower stability and antenna dyesof low sensitivity/higher stability, the antenna dyes of the hybridantenna package have absorbance maximums approximately matching thewavelength of the radiation generating device (110). According to oneexemplary embodiment, the media processing system (100) may include aradiation generating device configured to produce one or more laserswith wavelength values of approximately 650 nm, approximately 780 nm,and/or approximately 300 nm to approximately 600 nm. By matching thewavelength values of the radiation generating device(s) (110), imageformation is maximized.

As mentioned, a number of dyes having varying absorbance maximums may beused in the above-mentioned coatings to act as radiation absorbingantenna dyes. Generally speaking, antenna dyes of cyanine and porphyrintypically exhibit high sensitivity/lower stability radiationcharacteristics while naphthalocyanines typically exhibit lowsensitivity/higher stability characteristics.

According to one exemplary embodiment, high sensitivity/lower stabilityradiation absorbing antenna dyes having absorbance maximums atapproximately 780 nm that may be incorporated into the present antennadye package include, but are in no way limited to, many indocyanineIR-dyes such as IR780 iodide (Aldrich 42,531-1) (1) (3H-Indolium,2-[2-[2-chloro-3-[(1,3-dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl]ethenyl]-3,3-dimethyl-1-propyl-,iodide (9CI)), IR783 (Aldrich 54,329-2) (2)(2-[2-[2-Chloro-3-[2-[1,3-dihydro-3,3-dimethyl-1-(4-sulfobutyl)-2Hindol-2-ylidene]-ethylidene]-1-cyclohexen-1-yl]-ethenyl]-3,3-dimethyl-1-(4-sulfobutyl)-3H-indoliumhydroxide, inner salt sodium salt) Additionally, low sensitivity/higherstability dyes having absorbance maximums at approximately 780 nm may beused including, but in no way limited to NIR phthalocyanine orsubstituted phthalocyanine dyes such as Cirrus 715 dye from Avecia,YKR186, and YKR3020 from Yamamoto chemicals

Similarly, high sensitivity/lower stability radiation absorbing antennadyes having absorbance maximums at approximately 650 nm that may beincorporated into the present antenna dye package include, but are in noway limited to, many indolium of phenoxazine dyes and cyanine dyes suchas cyanine dye CS172491-72-4. Additionally, low sensitivity/higherstability dyes having absorbance maximums at approximately 650 nm may beused including, but in no way limited to many commercially availablephthalocyanine dyes such as pigment blue 15.

Further, radiation absorbing antenna dyes having absorbance maximums atapproximately 650 nm that may be incorporated into the present antennadye package according to their extinction coefficient include, but arein no way limited to, dye 724 (3H-Indolium,2-[5-(1,3-dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)-1,3-pentadienyl]-3,3-dimethyl-1-propyl-,iodide) (λ max=642 nm), dye 683 (3H-Indolium,1-butyl-2-[5-(1-butyl-1,3-dihydro-3,3-dimethyl-2H-indol-2-ylidene)-1,3-pentadienyl]-3,3-dimethyl-,perchlorate (λ max=642.nm), dyes derived from phenoxazine such asOxazine 1 (Phenoxazin-5-ium, 3,7-bis(diethylamino)-, perchlorate) (λmax=645 nm), available from “Organica Feinchemie GmbH Wollen.”Appropriate antenna dyes applicable to the present exemplary system andmethod may also include but are not limited to phthalocyanine dyes withlight absorption maximum at/or in the vicinity of 650 nm.

Moreover, high sensitivity/lower stability radiation absorbing antennadyes having absorbance maximums at approximately 405 nm that may beincorporated into the present antenna dye package include, but are in noway limited to, cyanine and porphyrin dyes such as etioporphyrin 1 (CAS448-71-5). Additionally, low sensitivity/higher stability dyes havingabsorbance maximums at approximately 405 nm may be used including, butin no way limited to, phthalocyanines and naphthalocyanines such asethyl 7-diethylaminocoumarin-3-carboxylate (λ max=418 nm).

Radiation antennae which can be incorporated into the present antennadye package according to their extinction coefficient for optimizationin the blue (˜405 nm) and indigo wavelengths can include, but are in noway limited to, aluminum quinoline complexes, porphyrins, porphins, andmixtures or derivatives thereof. Non-limiting specific examples ofsuitable radiation antenna can include1-(2-chloro-5-sulfophenyl)-3-methyl-4-(4-sulfophenyl)azo-2-pyrazolin-5-onedisodium salt (λmax=400 nm); ethyl 7-diethylaminocoumarin-3-carboxylate(λ max=418 nm); 3,3′-diethylthiacyanine ethylsulfate (λmax=424 nm);3-allyl-5-(3-ethyl-4-methyl-2-thiazolinylidene)rhodanine (λ max=430 nm)(each available from Organica Feinchemie GmbH Wolfen), and mixturesthereof.

Non-limiting specific examples of suitable aluminum quinoline complexescan include tris(8-hydroxyquinolinato)aluminum (CAS 2085-33-8), andderivatives such as tris(5-cholor-8-hydroxyquinolinato)aluminum (CAS4154-66-1),2-(4-(1-methyl-ethyl)-phenyl)-6-phenyl-4H-thiopyran-4-ylidene)-propanedinitril-1,1-dioxide(CAS 174493-15-3), 4,4′-[1,4-phenylenebis(1,3,4-oxadiazole-5,2-diyl)]bisN,N-diphenyl benzeneamine (CAS 184101-38-0),bis-tetraethylammonium-bis(1,2-dicyano-dithiolto)-zinc(II) (CAS21312-70-9),2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-4,5-dihydro-naphtho[1,2-d]1,3-dithiole,all available from Syntec GmbH.

Non-limiting examples of specific porphyrin and porphyrin derivativescan include etioporphyrin 1 (CAS 448-71-5), deuteroporphyrin IX 2,4 bisethylene glycol (D630-9) available from Frontier Scientific, andoctaethyl porphrin (CAS 2683-82-1), azo dyes such as Mordant Orange (CAS2243-76-7), Merthyl Yellow (CAS 60-11-7), 4-phenylazoaniline (CAS60-09-3), Alcian Yellow (CAS 61968-76-1), available from Aldrichchemical company, and mixtures thereof. Exemplary methods of forming theabove-mentioned coating, as well as methods for forming images on thecoating are described in further detail below.

EXEMPLARY COATING FORMING METHOD

FIG. 2 is a flowchart illustrating a method of forming the presenttwo-phase radiation image-able thermochromic coating, according to oneexemplary embodiment. In general, a method of forming the image-ablethermochromic coating includes preparing the radiation-curable polymermatrix with an acidic activator species dissolved therein (step 200),preparing a low-melting eutectic of a leuco-dye (step 210), and evenlydistributing the low-melting eutectic of a leuco-dye in the radiationcurable polymer matrix (step 220). Further details of the exemplarycoating forming method will now be described in further detail belowwith reference to FIGS. 3 and 4.

As mentioned with reference to FIG. 2, a first step of the presentexemplary coating formation method includes preparing theradiation-curable polymer matrix with an acidic activator speciestherein (step 200). FIG. 3 further illustrates an exemplary method forpreparing the radiation-curable polymer matrix, according to oneexemplary embodiment. As illustrated in FIG. 3, the radiation-curablepolymer matrix may be prepared by first melting the acidic,proton-donating activator species together (step 300). In someembodiments, multiple activators can be used, e.g., multiple activatorsystems having coequal performance values to systems having a primaryactivator and secondary activator(s). While the present exemplary methodincludes the step of melting the activators together to acceleratedissolution of activator species that may exhibit poor solubility in theradiation curable polymer, the step of melting the activators togetheris optional. Rather, in many cases, the activators may be directlydissolved in the radiation-curable polymer without preliminary melting.

Once the desired activators have been optionally melted together (step300), the melted activators are added to the radiation-curable polymer(step 310). According to one exemplary embodiment, the proton-donatingactivator species are dissolved into the radiation-curable polymer.Dissolution of the proton-donating activator species may be facilitatedby the introduction of agitation into the radiation-curable polymer.Dissolution of the proton-donating activator species in theradiation-curable polymer (step 310) will provide for a substantiallyeven distribution of the activators throughout the polymer.

Once the desired activators have been dissolved in the radiation curablepolymer (step 310), one or more radiation absorbing antenna dyes areadded to the radiation-curable polymer (step 320). According to thepresent exemplary method, the above-mentioned hybrid antenna package maybe introduced to the two phases of the present exemplary coatingaccording to three different methodologies. According to a firstexemplary embodiment, the antenna dyes with very high laser radiationabsorbance (extinction coefficient) and, typically, not very goodphoto-stability may be dissolved/uniformly distributed in the coatingpolymer matrix phase. According to this first exemplary embodiment,antenna dyes with lower laser radiation absorbance (extinctioncoefficient) but good photo-stability forming the second component ofthe hybrid antenna dye package may be dissolved/uniformly distributed inthe leuco-dye phase.

According to a second exemplary embodiment, the antenna dyes of thehybrid antenna package may be distributed with the antenna dyes withvery high laser radiation absorbance (extinction coefficient) and,typically, not very good photo-stability dissolved/uniformly distributedin the leuco-dye phase. According to this second exemplary embodiment,the antenna dyes with lower laser radiation absorbance (extinctioncoefficient) but good photo-stability may be dissolved/uniformlydistributed in the coating polymer matrix phase.

According to yet a third exemplary embodiment, the antenna dyes of bothantenna dye groups may be uniformly distributed and/or dissolved in bothphases of the thermochromic coating. Regardless of the antenna dyedistribution, the selected antenna dyes may be selected as havingabsorbance maximums associated with the wavelength(s) of the radiationgenerating device(s) (110). According to one exemplary embodiment, theantenna dyes are dissolved into the various phases to provide asubstantially even distribution thereof.

Once the radiation-curable polymer matrix is formed (step 200; FIG. 2),a low-melting eutectic of the leuco dye phase may also be formed (step210; FIG. 2). According to one exemplary embodiment illustrated in FIG.4, the leuco dye phase is formed by first providing the color-former(step 400). As mentioned previously, the color-former may include, butis in no way limited to, leuco-dye and/or leco-dye alloy. As usedherein, the term “color-former” refers to any composition that changescolor upon application of energy. Color-formers may include, but are inno way limited to, leuco dyes, photochromic dyes, or the like. Forexample, the color-former may include leuco dyes, such as fluoran,isobenzofuran, and phthalide-type leuco dyes. The term “color-former”does not infer that color is generated from scratch, as it includesmaterials that can change in color, as well as materials that can becomecolored from a colorless or more transparent state or a different color.The resulting molten mixture may be referred to as a molten color-formerphase. Additionally, according to one exemplary embodiment, a meltingaid may be combined with the above-mentioned color-former (step 410).The melting aid may be a crystalline organic solid melted with thecolor-former, according to one exemplary embodiment. Melting aids aretypically crystalline organic solids that can be melted and mixed with aparticular color-former. For example, most color-formers are alsoavailable as a solid particulate that is soluble in standard liquidsolvents. Thus, the color-former and melting aid can be mixed and heatedto form a molten mixture. Upon cooling, a color-former phase ofcolor-former and melting aid is formed that can then be ground into apowder.

When the color-former and the melting aid are combined (step 410), oneor more radiation absorbing dyes may also be mixed with the color-former(step 420), according to one exemplary embodiment. As mentionedpreviously, the radiation absorbing dyes that are mixed with thecolor-former may be selected based on the wavelength or range ofwavelengths produced by the radiation generating device(s).

Additionally, as mentioned previously, the radiation absorbing dyes thatare mixed with the color-former may be mixed according to one of threedifferent embodiments. According to a first exemplary embodiment, theantenna dyes with very high laser radiation absorbance (extinctioncoefficient) and, typically, not very good photo-stability may bedissolved/uniformly distributed in the coating polymer matrix phase andthe antenna dyes with lower laser radiation absorbance (extinctioncoefficient) but good photo-stability forming the second component ofthe hybrid antenna dye package may be dissolved/uniformly distributed inthe leuco-dye phase. According to a second exemplary embodiment, theantenna dyes with very high laser radiation absorbance (extinctioncoefficient) and, typically, not very good photo-stabilitydissolved/uniformly distributed in the leuco-dye phase, while theantenna dyes with lower laser radiation absorbance (extinctioncoefficient) but good photo-stability may be dissolved/uniformlydistributed in the coating polymer matrix phase. According to yet athird exemplary embodiment, the antenna dyes of both antenna dye groupsare uniformly distributed and/or dissolved in both phases of thethermochromic coating. While the present exemplary method includes aplurality of radiation absorbing dyes in each of the two phases, it willbe appreciated that the radiation absorbing antenna dyes can be presentin either or both of the various phases.

Once the above-mentioned components are melted, the molten low-meltingeutectic of the leuco dye phase is allowed to cool and the particle sizeof the low-melting eutectic of the leuco dye phase is reduced (step430). The particle size of the low-melting eutectic of the leuco dyephase may be reduced by any number of known methods including, but in noway limited to, milling and/or grinding.

Returning again to the method illustrated in FIG. 2, once both theradiation-curable polymer matrix and the low-melting eutectic of theleuco-dye phase are formed, the low melting eutectic is distributed inthe polymer matrix (step 220). According to one exemplary embodiment,the low-melting eutectic of the leuco-dye phase may be distributed inthe polymer with the aid of continuous agitation during introduction ofthe low melting eutectic in the polymer matrix.

When the two-phase radiation image-able thermochromic coating is formedas described above, it may be applied to any number of desiredsubstrates including, but in no way limited to, polymer, paper, ceramic,glass, metal, and the like. According to one exemplary embodiment, thedual band radiation image-able thermochromic coating may be applied to adesired substrate using any number of known coating systems and methodsincluding, but in no way limited to, doctor blade coating, gravurecoating, reverse roll coating, meyer rod coating, extrusion coating,curtain coating, air knife coating, and the like.

Once the above-mentioned coating is formed on a radiation image-abledisk (130; FIG. 1), data may be formed on the data surface of the firstside (140), and/or a desired image may be formed via selective radiationexposure on the second side (150). FIG. 5 illustrates one exemplarymethod for forming a desired image on the second side (150) of theradiation imageable disk (130), according to one exemplary embodiment.As illustrated in FIG. 5, the image formation method begins by firstgenerating the desired image (step 500). According to one exemplaryembodiment, generating the desired image may include forming a graphicalrepresentation of the desired image using any number of user interfacesand converting the graphical representation into a number of machinecontrollable commands using the firmware (123; FIG. 1) and/or theprocessor (125; FIG. 1) of the media processing system (100; FIG. 1).

Continuing with FIG. 5, the radiation image-able disk may then be placedadjacent to the radiation generating device(s) (110; FIG. 1) with theradiation image-able coating in optical communication with the radiationgenerating device(s) (step 510). With the radiation image-able coatingin optical communication with the radiation generating device(s) (step510), the radiation image-able coating may then be selectively exposedto the radiation generating device(s) to form the desired image (step520).

According to the present exemplary embodiment, the two-phase radiationimage-able thermochromic coating made with the above-mentioned hybridantenna package exhibits improved marking sensitivity and shelf-lifereliability when compared to traditional image-able thermochromiccoatings. More specifically, the present two-phase radiation exhibits ahigh marking sensitivity once formed due to the presence of the highextinction coefficient/lower stability antenna dye. Additionally, due tothe presence of the lower extinction coefficient/higher stabilityantenna dye, sufficient marking sensitivity may be maintained in thecoating even after exposure to ambient light for long periods of time.

The preceding description has been presented only to illustrate anddescribe the present method and apparatus. It is not intended to beexhaustive or to limit the disclosure to any precise form disclosed.Many modifications and variations are possible in light of the aboveteaching. It is intended that the scope of the disclosure be defined bythe following claims.

1. A radiation image-able coating, comprising: a first phase including aradiation curable polymer matrix and an activator disposed in saidradiation curable polymer matrix; a second phase insolubly distributedin said first phase, said second phase including a color-former; and ahybrid antenna dye package distributed in at least one of said first andsecond phase, wherein said hybrid antenna dye package includes at leasta first antenna dye having a high extinction coefficient and a secondantenna dye having a low extinction coefficient.
 2. The coating of claim1, wherein said antenna dye package is distributed in both said firstphase and said second phase.
 3. The coating of claim 1, wherein saidcolor-former comprises a low-melting eutectic of one of a leuco-dye or aleuco-dye alloy.
 4. The coating of claim 3, wherein said color-formercomprises a low-melting eutectic of a fluorane leuco-dye.
 5. The coatingof claim 1, wherein both said first antenna dye and said second antennadye of said hybrid antenna dye package have an absorbance maximumwavelength comprising one of approximately 780 nm, approximately 650 nm,or approximately 405 nm.
 6. The coating of claim 1, wherein: said firstantenna dye has an extinction coefficient greater than approximately100,000 L M⁻¹ cm⁻¹; and said second antenna dye has an extinctioncoefficient less than approximately 100,000 L M⁻¹ cm⁻¹.
 7. The coatingof claim 1, wherein said activator comprises an acidic activator speciesdissolved in said first phase.
 8. The coating of claim 1, wherein saidsecond phase comprises a dispersion within said first phase.
 9. Thecoating of claim 1, wherein said second phase further comprises amelting aid configured to decrease the melting temperature of saideutectic.
 10. A method of forming a radiation image-able coatingcomprising: preparing a radiation-curable polymer matrix including anacidic activator species; forming a low-melting eutectic of a leuco-dyephase; distributing said low-melting eutectic of a leuco-dye phase insaid polymer matrix; and sensitizing said radiation image-able coatingwith a hybrid antenna dye package, wherein said hybrid antenna dyepackage includes at least a first antenna dye having a high extinctioncoefficient and a second antenna dye having a low extinctioncoefficient.
 11. The method of claim 10, wherein said sensitizing saidradiation image-able coating with a hybrid antenna dye package furthercomprises distributing said hybrid antenna dye package in saidradiation-curable polymer matrix.
 12. The method of claim 10, whereinsaid sensitizing said radiation image-able coating with a hybrid antennadye package further comprises distributing said antenna dye package insaid low-melting eutectic of a leuco-dye phase.
 13. The method of claim10, further comprising selecting said hybrid antenna dye package to havean absorbance maximum wavelength to correspond to a radiation generatingdevice having a wavelength of approximately 780 nm.
 14. The method ofclaim 10, further comprising selecting said hybrid antenna dye packageto have an absorbance maximum wavelength to correspond to a radiationgenerating device having a wavelength of approximately 650 nm.
 15. Themethod of claim 10, further comprising selecting said hybrid antenna dyepackage to have an absorbance maximum wavelength to correspond to aradiation generating device having a wavelength of approximately 405 nm.16. The method of claim 10, wherein said preparing a radiation-curablepolymer matrix including an acidic activator species comprises: meltinga plurality of acidic activator species; and adding said meltedactivators to a radiation-curable polymer.
 17. The method of claim 16,further comprising adding one of said first antenna dye having a highextinction coefficient or said second antenna dye having a lowextinction coefficient to said radiation-curable polymer.
 18. The methodof claim 10, wherein said forming a low-melting eutectic of a leuco-dyephase comprises: providing a color-former; combining a melting aid withsaid color-former.
 19. The method of claim 18, further comprising addingone of said first antenna dye having a high extinction coefficient orsaid second antenna dye having a low extinction coefficient to saidcolor-former.
 20. The method of claim 18, further comprising reducing aparticle size of said color-former.
 21. The method of claim 10, wherein:said first antenna dye has an extinction coefficient greater thanapproximately 100,000 L Mol⁻¹ cm⁻¹; and said second antenna dye has anextinction coefficient less than approximately 100,000 L Mol⁻¹ cm⁻¹. 22.A method of forming an image on a substrate comprising: forming aradiation image-able coating on a desired substrate, wherein saidradiation image-able coating includes a first phase including aradiation curable polymer matrix and an activator disposed in saidradiation curable polymer matrix, a second phase insolubly distributedin said first phase, said second phase including a color-former, and ahybrid antenna dye package distributed in at least one of said first andsecond phase, wherein said hybrid antenna dye package includes at leasta first antenna dye having a high extinction coefficient and a secondantenna dye having a low extinction coefficient; and selectivelyexposing said radiation image-able coating to at least one radiationsource, wherein said radiation source has a wavelength associated withan absorbance maximum wavelength of said hybrid antenna dye package. 23.The method of claim 22, wherein said hybrid antenna dye package isdistributed in both said first phase and said second phase.
 24. Themethod of claim 22, wherein said radiation source comprises a laserhaving a wavelength of one of approximately 780 nm, approximately 650nm, or approximately 405 nm.
 25. The method of claim 22, wherein: saidfirst antenna dye has an extinction coefficient greater thanapproximately 100,000 L Mol⁻¹ cm⁻¹; and said second antenna dye has anextinction coefficient less than approximately 100,000 L Mol⁻¹ cm⁻¹. 26.The method of claim 22, wherein said first antenna dye is distributed insaid first phase and said second antenna dye is distributed in saidsecond phase.
 27. The method of claim 22, wherein said second antennadye is distributed in said first phase and said first antenna dyedistributed in said second phase.
 28. A system for forming an image on asubstrate, comprising: a radiation generating device configured togenerate radiation having a first wavelength; a substrate disposedadjacent to said radiation generating device; and a radiation image-ablecoating disposed on said substrate, wherein said radiation image-ablecoating includes a first phase including a radiation curable polymermatrix and an activator disposed in said radiation curable polymermatrix, a second phase insolubly distributed in said first phase, saidsecond phase including a color-former, and a hybrid antenna dye packagedistributed in at least one of said first and second phase, wherein saidantenna dye package includes at least a first antenna dye having highextinction coefficient and a second antenna dye having a low extinctioncoefficient.
 29. The system of claim 28, wherein said antenna dyepackage is distributed in both said first phase and said second phase.30. The system of claim 28, wherein said color-former comprises alow-melting eutectic of one of a leuco-dye or a leuco-dye alloy.